public class BinaryTree {
    static class TreeNode {
        public char val;
        public TreeNode left;
        public TreeNode right;

        public TreeNode(char val) {
            this.val = val;
        }
    }

    /**
     * 手动创建二叉树，创建完成之后，返回根节点
     */

    public TreeNode createTree() {
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');

        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        E.right = H;

        return A;
    }

    //递归前序遍历
    public void preOrder(TreeNode root) {
        if(root == null) {
            return;
        }
        System.out.println(root.val+" ");
        preOrder(root.left);
        preOrder(root.right);
    }

    //递归中序遍历
    public void inOrder(TreeNode root) {
        if(root == null) {
            return;
        }
        inOrder(root.left);
        System.out.println(root.val+" ");
        inOrder(root.right);
    }

    //递归后序遍历
    public void postOrder(TreeNode root) {
        if(root == null) {
            return;
        }
        postOrder(root.left);
        postOrder(root.right);
        System.out.print(root.val+" ");
    }

    //获取树中节点的个数
    public int nodeSize = 0;
    public void size(TreeNode root) {
        if(root == null) {
            return;
        }
        nodeSize++;
        size(root.left);
        size(root.right);
    }

    public int size2(TreeNode root) {
        if(root == null) {
            return 0;
        }
        return size2(root.left) + size2(root.right)+1;
    }

    // 获取叶子节点的个数
    public int leftSize = 0;
    public void getLeafNodeCount(TreeNode root) {
        if(root == null) {
            return;
        }
        if(root.left == null && root.right == null) {
            leftSize++;
        }
        getLeafNodeCount(root.left);
        getLeafNodeCount(root.right);
    }

    public int getLeafNodeCount2(TreeNode root) {
        if(root == null) {
            return 0;
        }
        if(root.left == null && root.right == null) {
            return 1;
        }
        return getLeafNodeCount2(root.left)+getLeafNodeCount2(root.right);
    }

    //获取第K层节点的个数
    public int getKLevelNodeCount(TreeNode root,int k) {
        if(root == null) {
            return 0;
        }
        if(k == 1) {
            return 1;
        }
        return getKLevelNodeCount(root.left,k-1)+getKLevelNodeCount(root.right,k-1);
    }

    // 获取二叉树的高度 时间复杂度O(N)  空间复杂度O(logN)
    public int getHeight(TreeNode root) {
        if(root == null) {
            return 0;
        }
        int leftHeight = getHeight(root.left);
        int rightHeight = getHeight(root.right);

        return Math.max(leftHeight,rightHeight)+1;
    }

    // 获取二叉树的高度
    public int getHeight2(TreeNode root) {
        if(root == null) {
            return 0;
        }
        //int leftHeight = getHeight2(root.left);
        //int rightHeight = getHeight2(root.right);

        //return leftHeight > rightHeight ? leftHeight+1: rightHeight+1;
        return getHeight2(root.left) > getHeight2(root.right) ?
                getHeight2(root.left)+1: getHeight2(root.right)+1;
        //上行 return 语句 有重复，getHeight(root.left)与 getHeight(root.righ)会算两遍 在 leetcode 可能会超时
    }

    //检测值为

}
